The present disclosure generally relates to a relatively low-speed bus message protocol, and more particularly relates to methods and circuitry for acoustic object and/or gesture detection and/or recognition using relatively low-speed bus time stamping and triggering.
The Inter-Integrated Circuit (I2C) interface is typically used for attaching lower-speed peripheral Integrated Circuits (ICs) to higher-speed processors and microcontrollers. Lower-speed peripheral ICs are commonly referred to as slave devices, whereas a higher-speed processor or microcontroller is commonly referred to as a master device. Often, a slave device can be coupled to a peripheral device such as a sensor, a gyroscope, a compass, a microphone, and the like. The slave device can be configured to monitor and/or control operations of the peripheral device coupled to the slave device.
In the I2C message protocol, a simultaneous operation by two or more slave devices can utilize a common trigger signal (e.g., generated by a master device), which is provided independent of an I2C low-speed serial bus. Similarly, in order to determine when an event occurred (e.g., a measurement performed by a peripheral device coupled to a slave device), each slave device uses a dedicated line or trace feeding back to the master device for signaling to the master device a time when the event occurs. For each slave device, the master device can capture a state of a real time clock (i.e., time of event, or timestamp of event) when the master device receives an event marker signal from the slave device over the separate dedicated line. The disadvantage of this approach is a number of additional communication lines (i.e., board traces) between the master device and the slave devices, and the additional signal pins that are required.